Glacial outburst floods, caused by collapsing ice or sediment dams, pose a significant threat globally, having killed over 12,000 people historically. Millions live in at-risk areas, particularly in India, China, and Pakistan. A 2023 study identified 120 glacier-dammed lakes in Alaska, 106 of which drained since 1985. Juneau, Alaska, implemented protective barriers this year, largely preventing property damage despite record high floodwaters. While climate change is causing glacier retreat, potentially reducing future outburst floods in some areas, it also creates instability in higher-altitude glaciers, leading to new risks.

Prepared by Olivia Bennett and reviewed by editorial team.